Changes in Bacterial Community Structure During Preceding and Degraded Period of Cyanobacterial Bloom in a Bay of the Taihu Lake

Abstract

Diversity of bacterioplankton in March and September (2004) in the eutrophic Meiliang Bay was determined by 16S rRNA gene sequences. Result showed that community composition, especially the most dominant bacteria during preceding and degraded period of Cyanobacterial bloom was different. Clones in the March clone library (M3) were mostly affiliated with Bacteroidetes (42.7%), β-Proteobacteria (18.4%), α-Proteobacteria (16.5%) and Actinobacteria (16.5%), while clones in the September clone library (M9) were mainly affiliated with cyanobacteria (28.8%), β-Proteobacteria (25.0%), Actinobacteria (17.3%) and α-Proteobacteria (15.4%). Greater diversity in sequence composition was found in M9 (11 clusters) than that in M3 (7 clusters). Compared with related study, α-Proteobacteria, β-Proteobacteria and Actinobacteria were widely found in the Taihu Lake, whereas γ-Proteobacteria and Firmicutes were more frequently detected in sediments, and Bacteroidetes were abundant in water. Most 16S rRNA gene sequences retrieved from the two libraries were closely related to freshwater bacteria in different aquatic ecosystems including oligo-, meso-and eu-trophic lakes. A large number of clones were originated from the Yangtze River. The sequences represented in marine habitats were rarely found except the members of Bacteroidetes. Fig 2, Tab 3, Ref 21